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S Fujisawa

Publications and source records attributed to S Fujisawa.

At least 19 recordsLinked to original sources
PubMed2006

In vivo, competitive blockade of N-methyl-D-aspartate receptors induces rapid changes in filamentous actin and drebrin A distributions within dendritic spines of adult rat cortex.

In vitro studies have demonstrated that prolonged N-methyl-D-aspartate receptor (NMDAR) blockade triggers a homeostatic up-regulation of NMDARs at synapses. Such upregulation can also be seen within 30 min in vivo in adult rats, implicating trafficking of reserve pools of NMDARs. Here, we evaluated the involvement of filamentous actin (F-actin), the major cytoskeletal component in spines, in this rapid in vivo homeostatic response, using biotinylated phalloidin as its probe. We also immuno-labeled spines for drebrin A, an F-actin-binding protein found at excitatory synapses and with a proposed role of modulating F-actin's cross-linking with one another and interactions with NMDARs. Quantitative 2-D analysis of ultrastructural images revealed that NMDAR blockade increased filamentous actin labeling per spine by 62.5% (P<0.005). The proportion of dendritic spines immuno-labeled for drebrin A also increased significantly, from 67.5% to 85% following NMDAR blockade (P<0.001), especially among larger spines. The frequency distributions of spine widths and postsynaptic density lengths were not affected by the D-(+)-2-amino-5-phosphonopentanoic acid (D-APV) treatment. However, the average postsynaptic density length was reduced by 25 nm among the fewer, drebrin A immuno-negative spines, indicating that drebrin A confers stability to synapse size. We propose that, in a homeostatic in vivo response, increases of drebrin A and F-actin within spines can enhance NMDAR trafficking by reducing cytoskeletal rigidity within the spine cytoplasm without changing the overt morphology of axo-spinous synapses. Alternatively or in addition, the cytoskeletal redistribution within spine cytoplasm may be triggered by the D-APV-induced, homeostatic up-regulation of NMDAR.

Actin Cytoskeleton↗
PubMed2006

(Meth)acrylate monomer-induced cytotoxicity and intracellular Ca(2+) mobilization in human salivary gland carcinoma cells and human gingival fibroblast cells related to monomer hydrophobicity.

To elucidate a possible link between the cytotoxicity and Ca(2+) mobilization by (meth)acrylates, we investigated the cell survival of and change in [Ca(2+)](i) in human salivary gland (HSG) cells (salivary gland carcinoma cell line) and human gingival fibroblasts (HGF) cells treated separately with 9 (meth)acrylate monomers used in dentistry. The cell survival was determined by the MTT method, and the [Ca(2+)](i) changes after the stimulation with the (meth)acrylate monomers were measured in floating indo-1/AM-loaded cells in Ca(2+)-free medium. For both HSG and HGF cells, the cytotoxicity of the monomers was approximately proportional to their hydrophobicity (logP). No increase in [Ca(2+)](i) was found with hydrophilic monomers, even with 10mm stimulation. [Ca(2+)](i) elevation by hydrophobic monomers occurred in a dose- and hydrophobic-dependent manner. The [Ca(2+)](i) change in HSG cells appeared as twin peaks, i.e., an initial sharp peak followed by a delayed broad one; whereas with the HGF cells only a single broad peak was seen, possibly dependent on their membrane quality. Pretreatment with n-butanol or methylmethacrylate enhanced the butylmethacrylate-induced [Ca(2+)](i) elevation, suggesting the [Ca(2+)](i) elevation by (meth)acrylate may be related to monomer hydrophobicity and cell type. The causal link between the cytotoxicity and [Ca(2+)](i) mobilization of monomers is discussed.

Butanols↗
PubMed2005

A comparative study of the antioxidant/prooxidant activities of eugenol and isoeugenol with various concentrations and oxidation conditions.

Eugenol (compound in , 4-allyl-2-methyoxyphenol) and isoeugenol (compound in , 4-propenyl-2-methoxyphenol), both used as a flavor agent in cosmetic and food products, have both prooxidant and antioxidant activities. Their adverse effects such as allergic and inflammatory reaction may be due to their prooxidant activity. To clarify the mechanisms of their cytotoxicity and the factors affecting their antioxidant/prooxidant activities, we investigated the cytotoxicity, ROS production, and cellular glutathione (GSH) levels induced by eugenol and isoeugenol in a human submandibular cell line. The cytotoxicity (MTT method) of eugenol was 1 order of magnitude lower than that of isoeugenol (CC50: eugenol, 0.395 mM; isoeugenol, 0.0523 mM); and ROS production (CDF staining) was induced significantly by isoeugenol, but not by eugenol. Under treatment with H2O2 (100 microM) plus horseradish peroxidase (1 microg/ml) for 30 min or with visible light irradiation for 5 min, eugenol caused biphasic ROS production characterized by enhanced at lower eugenol concentrations (5-10 microM) and decreased at higher concentrations (500 microM). In contrast, isoeugenol enhanced ROS production over a wide range of concentrations (5-500 microM). Isoeugenol at 1000 microM significantly reduced GSH levels compared with eugenol at the same concentration. The high cytotoxicity of isoeugenol may be attributed to its induction of high ROS production and low GSH levels, possibly as a result of benzyl radical formation. In contrast, the cytotoxicity of eugenol is likely to be mediated by ROS-independent mechanisms, possibly involving phenoxyl radicals and/or eugenol quinone methide.

Antioxidants↗
PubMed2005

Comparison between reduced intensity and conventional myeloablative allogeneic stem-cell transplantation in patients with hematologic malignancies aged between 50 and 59 years.

To evaluate the efficacy of reduced-intensity stem-cell transplantation (RIST), we retrospectively compared outcomes of 207 consecutive Japanese patients aged between 50 and 59 years with hematologic malignancies who received RIST (n=70) and conventional stem-cell transplantation (CST) (n=137). CST recipients received total body irradiation (TBI)-based or busulfan/cyclophosphamide-based regimens. RIST regimens were purine analog-based (n=67), 2 Gy TBI-based (n=2), and others (n=1). Most CST recipients (129/137) received calcineurin inhibitors and methotrexate as graft-versus-host (GVHD) prophylaxis, while 32 RIST recipients received cyclosporin. In all, 23 CST and five RIST recipients died without disease progression within 100 days of transplant. Grade II to IV acute GVHD occurred in 56 CST and 38 RIST recipients. There was no significant difference in overall survival (OS) and progression-free survival between CST and RIST. On multivariate analysis on OS, five variables were significant: preparative regimens (CST vs RIST) (hazard ratio=1.92, 95% confidence interval, 1.25-2.97; P=0.003), performance status (2-4 vs 0-1) (2.50, 1.51-4.16; P<0.001), risk of underlying diseases (1.85, 1.21-2.83; P=0.004), acute GVHD (2.57, 1.72-3.84; P<0.001), and CML (0.38, 0.21-0.69; P=0.002). We should be careful in interpreting results of this small-sized retrospective study; however, reduced regimen-related toxicity might contribute to better survival in RIST. The low relapse rates following RIST suggest a strong antitumor activity through allogeneic immunity.

Female↗
PubMed2005

Relationship between intracellular ROS production and membrane mobility in curcumin- and tetrahydrocurcumin-treated human gingival fibroblasts and human submandibular gland carcinoma cells.

OBJECTIVE: Curcumin is a well-known chemopreventive agent of oral cancers as well as stomach and intestinal cancers. The relationship between reactive oxygen species (ROS) production and cell membrane mobility was investigated to clarify the pro-oxidant mechanism of curcumin and tetrahydrocurcumin (TH-curcumin). METHODS: The intracellular ROS production and membrane mobility by curcumin or TH-curcumin were measured in human submandibular adenocarcinoma cells (HSGs) and human primary gingival fibroblasts (HGFs). ROS and mobility were measured by 5-(and -6)-carboxy-2',7'-dichlorofluorescein diacetate staining and fluorescence recovery after photo bleaching, respectively. RESULTS: Curcumin produced ROS dose-dependently. ROS appeared in the region surrounding the cell membrane. The membrane mobility coefficient of the curcumin-treated cells was significantly lower than that of control cells. The lowered membrane mobility induced by curcumin was reversed by the addition of glutathione, an antioxidant. In contrast, TH-curcumin did not affect the ROS production or the membrane mobility coefficient. The alternations induced by curcumin treated HSG cells were greater than those by HGF cells. CONCLUSION: The reduction in membrane mobility induced by curcumin was attributed to ROS production. The oxidative effects of curcumin may be related to the structure of the alpha, beta-unsaturated carbonyl moiety as well as the phenolic OH group of this compound.

Adenocarcinoma↗
PubMed2004

Pleasant feeling from watching a comical video enhances free radical-scavenging capacity in human whole saliva.

OBJECTIVE: Free radicals have been implicated in aging, mutagenesis, inflammation and other pathological conditions. We conducted a study to clarify the relation between a pleasant feeling as a psychological eustress and free radical-scavenging capacity (FRSC) in saliva. METHODS: Saliva was collected from 27 healthy volunteers. FRSC before, during and after watching a cheerful comical video for 30 min was measured by using 1,1-diphenyl-2-picrylhydrazyl (DPPH). RESULTS: The median values of FRSC (micromol/ml) before, at 10 and 20 min during and after watching the video were 54.5, 66.8, 66.6 and 69.4, respectively. The FRSC values obtained after watching the video were significantly higher than those before watching it (P<.001). When the FRSC before watching was taken as 1, the value for the group that felt "Very good," "Good" or "Ordinary+Dull" while watching the video for 30 min was 1.38, 1.20 or 0.98, respectively (P<.01). CONCLUSION: Watching a comical video enhanced the FRSC in saliva; in addition, a pleasant feeling boosted it even more.

Adult↗
PubMed2004

Thiotepa/cyclophosphamide/TBI as a conditioning regimen for allogeneic hematopoietic stem cell transplantation in patients with myelodysplastic syndrome.

In all, 18 patients (30-56 years; median 49) with MDS underwent allogeneic HSCT from related (n=12) or unrelated (n=6) donors after a conditioning regimen comprising thiotepa, cyclophosphamide, and TBI. GVHD prophylaxis consisted of cyclosporine (n=15) or tacrolimus (n=3) with short-course methotrexate. Four patients had low-risk disease (refractory anemia or complete remission after chemotherapy) and 14 patients had high-risk disease (RAEB, RAEB-t, or AML). Grade II-IV acute GVHD developed in six patients and chronic GVHD in 10. With a median follow-up of 31 months, the 2-year survival probability is 75% for low-risk patients and 57% for high-risk patients. One patient died of leukemia and six of treatment-related causes. This conditioning regimen requires further study in patients with MDS.

Adult↗
PubMed2004

Kinetics of the radical scavenging activity of beta-carotene-related compounds.

To clarify the non-enzymatic radical-scavenging activity of beta-carotene-related compounds and other polyenes, we used differential scanning calorimetry to study the kinetics of radical polymerization of methyl methacrylate (MMA) by 2,2'-azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) in the absence or presence of polyenes under nearly anaerobic conditions at 70 degrees C, and analyzed the results with an SAR approach. The polyenes studied were all-trans retinol, retinol palmitate, calciferol, beta-carotene and lycopene. Polyenes produced a small induction period. The stoichiometric factor (n) (i.e. the number of radicals trapped by each inhibitor molecule) of polyenes was close to 0. Tetraterpenes (beta-carotene, lycopene) suppressed significantly more of the initial rate of polymerization (R(inh)) than did diterpenes (retinol, retinol palmitate). The inhibition rate constants (k(inh)) for the reaction of beta-carotene with AIBN- or BPO-derived radicals were determined to be 1.2-1.6x10(5) l/mol s, similar to published values. A linear relationship between (k(inh)) and the kinetic chain length (KCL) for polyenes was observed; as (k(inh)) increased, KCL decreased. KCL also decreased significantly as the number of conjugated double bonds in the polyenes increased. Polyenes, particularly beta-carotene and lycopene, acted as interceptors of growing poly-MMA radicals.

Calorimetry, Differential Scanning↗
PubMed2003

In vivo blockade of N-methyl-D-aspartate receptors induces rapid trafficking of NR2B subunits away from synapses and out of spines and terminals in adult cortex.

We investigated the role of in vivo synaptic activity upon trafficking of the N-methyl-D-aspartate (NMDA) receptor subunit, NR2B, at mature synapses by electron microscopic immunocytochemistry. In vivo blockade of NMDA receptors was achieved by applying the NMDA receptor antagonist, D-2-amino-5-phosphonovalerate (D-APV), onto the cortical surface of one hemisphere of anesthetized adult rats. Inactive L-2-amino-5-phosphonovalerate (L-APV) was applied to the contralateral hemisphere for within-animal control and to assess basal level of NR2B subunits at synapses. Within 30 min of D-APV treatment, we observed a decrease in the number of layer I axo-spinous asymmetric synapses that are positively immuno-labeled for the NR2B subunits. This decrease was paralleled by reductions in the absolute number of immuno-gold particles found at these synapses. The decrease of NR2B labeling was detectable in all five animals examined. Significant reductions were seen not only at post-synaptic densities, but also within the cytoplasm of spines and axon terminals. The data demonstrate that blockade of NMDA receptors induces trafficking of NR2B subunits out of synaptic membranes, spines, and terminals. This is in sharp contrast to a previous observation that NR2A subunits move into spines and axon terminals following in vivo blockade with D-APV. These findings point to yet unknown, NMDA receptor activity-dependent mechanisms that separately regulate the localization of NR2A and NR2B subunits at synapses.

Animals↗
PubMed2003

Nonmyeloablative stem cell transplantation with fludarabine and cyclophosphamide for patients with hematologic malignancies.

We conducted a multi-center phase I/II trial of nonmyeloablative stem cell transplantation for patients with hematologic malignancies. The aim of this trial was to assess the safety and feasibility of this treatment modality for older or younger patients with significant organ dysfunction, who could not be treated with conventional high dose chemoradiotherapy. Twelve patients were treated with a conditioning regimen consisting of fludarabine and cyclophosphamide, followed by peripheral blood stem cell transplantation from human leukocyte antigen (HLA) identical siblings. Nonhematologic toxicities were mild. Median time to absolute neutrophils above 0.5 x 10(9)/l, 1.0 x 10(9)/l and platelets above 50 x 10(9)/l were 8, 10 and 12 days, respectively. Donor dominant hematopoiesis was achieved in all patients, with or without donor leukocyte infusion. The cumulative incidence of acute and chronic graft-versus-host disease (GVHD) was 75 and 56%, respectively. Only one patient experienced early death within 100 days, caused by acute GVHD complicated by fungal infection. All patients except one achieved complete remission. With a median follow-up of 330 days, expected progression-free survival is 75%. Overall survival is 76%. Our study confirms that nonmyeloablative stem cell transplantation with cyclophosphamide and fludarabine conditioning is a safe and promising treatment for elderly patients with hematologic malignancies. A further study in large-scale setting is warranted.

Age Factors↗
PubMed2003

Interaction between 2-ethoxybenzoic acid (EBA) and eugenol, and related changes in cytotoxicity.

The liquid of 2-ethoxybenzoic acid cements is composed of 2-ethoxybenzoic acid and eugenol (4-allyl-2-methoxyphenol). Recently, eugenol was reported to produce radicals at a higher pH, which consequently directly damages cells. We examined here whether eugenol radicals are generated from the mixture of eugenol/calcium hydroxide, and also whether 2-ethoxybenzoic acid or acetylsalicylic acid scavenges radicals, using electron spin resonance spectroscopy. Radicals were generated from the mixture of eugenol/calcium hydroxide in 50% dimethylsulfoxide solution. The radical intensity of eugenol in 50% dimethylsulfoxide with 0.1 M sodium bicarbonate buffer (pH 9.5) was dose-dependently reduced by 2-ethoxybenzoic acid, whereas it was enhanced by acetylsalicylic acid. Next, we investigated the cytotoxic effect of eugenol on 2-ethoxybenzoic acid, acetylsalicylic acid, or calcium hydroxide on human pulp fibroblasts or a human submandibular gland cancer cell line. The cytotoxicity of EBA was decreased, whereas that of acetylsalicylic acid was increased by eugenol. In contrast, that of calcium hydroxide was not affected by eugenol. Human pulp fibroblast but not human submandibular gland cells showed a high resistance against calcium hydroxide. The generation of eugenol radicals in the liquid of 2-ethoxybenzoic acid cements caused by oxidation may be suppressed by 2-ethoxybenzoic acid.

Aspirin↗
PubMed2002

Arsenic trioxide therapy for relapsed or refractory Japanese patients with acute promyelocytic leukemia: need for careful electrocardiogram monitoring.

Recent studies have shown that arsenic trioxide (As(2)O(3)) can induce complete remission in patients with acute promyelocytic leukemia (APL). We tested the efficacy and safety of As(2)O(3) for the treatment of patients with APL who had relapsed from or become refractory to all-trans retinoic acid (ATRA) and conventional chemotherapy in a prospective study. As(2)O(3) at a dose of 0.15 mg/kg was administered until the date of bone marrow remission to a maximum of 60 days. In patients who achieved complete remission (CR), one additional course of As(2)O(3) was administered using the same dose for 25 days. Of 14 patients, 11 (78%) achieved CR. Six of 10 patients who achieved CR showed disappearance of PML-RARalpha transcript by RT-PCR assay. The duration of As(2)O(3)-induced CR ranged from 4 to 22 months (median, 8 months) at a median follow-up of 17 months. Adverse events included 13 electrocardiogram abnormalities (13 QTc prolongation, eight ventricular premature contraction, four nonsustained ventricular tachycardia and two paroxysmal supraventricular tachycardia), seven nausea and vomiting, four pruritus, three peripheral neuropathy, three fluid retention and one APL differentiation syndrome. Four patients received antiarrhythmic agents. Hyperleukocytosis developed in five patients and in three cytotoxic drugs were necessary. Other adverse events were relatively mild. As(2)O(3) treatment is effective and relatively safe in relapsed or refectory patients with APL. Cardiac toxicities in patients with QTc prolongation should be carefully monitored.

Adult↗
PubMed2001

XANES spectroscopy of a single neuron from a patient with Parkinson's disease.

Chemical state of transition metals such as iron in a single neuron of the substantia nigra (SN) from a patient with Parkinson's disease (PD) was studied in this paper, using autopsy midbrain specimens including SN. Parkinson's disease is one of the major neurodegenerative diseases. The excessive accumulation of iron and its chemical states in SN neurons are related to the oxidative damage leading to neuronal cell death. X-ray absorption fine structure spectroscopy (XAFS) with SR micro beam (10 microm) was used to investigate the chemical state of iron in the SN neurons. X-ray absorption near-edge structure (XANES) spectroscopy results showed that the chemical state of iron in the neuromelanin granules within SN neurons changed from ferrous (Fe2+) to ferric (Fe3+) ion in the process of neuronal degeneration.

Humans↗
PubMed2001

Biochemical and morphological changes during development of sugar cataract in Otsuka Long-Evans Tokushima fatty (OLETF) rat.

The relationship between the polyol pathway and sugar cataracts has been studied extensively using streptozotocin-induced diabetic rats and galactose fed rats as animal models for insulin-dependent diabetes mellitus (IDDM). In these models, sugar cataracts progress quickly, leading to rapid lenticular polyol accumulation in the early stages of cataract formation. In 1992, a new animal model of non-insulin-dependent diabetes mellitus (NIDDM), the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, was established. In the present study, we examined both biochemical and morphological changes in the lenses of the OLETF rats to determine whether these changes reflect those associated with diabetic cataract formation and to clarify their relationship with the polyol pathway. For the biochemical analysis, we measured the enzyme activity of aldose reductase (AR) and sorbitol dehydrogenase (SDH) and the sorbitol levels using 20, 40 and 60 week old OLETF or control Long-Evans Tokushima Otsuka (LETO) rats. Enzyme activities of AR and SDH, which were lower in 20 week old OLETF rats than in LETO rats, were increased in 60 week old OLETF rats. The lenticular sorbitol level of the OLETF rats was similar to the control level at 20 weeks of age, but it was markedly increased at 40 weeks of age, and slightly decreased at 60 weeks of age compared with rats at 40 weeks but not compared with controls. Slight lens fiber swelling was observed in the anterior and/or posterior subcapsular regions of 40 week old OLETF rats, accompanying elevated sorbitol level and slightly increased SDH activity in the lens. Swelling and liquefaction of lens fibers were observed in the subcapsular and supranuclear region of 60 week old OLETF rats, as well as decreased lenticular sorbitol, and markedly increased SDH activity compared with rats at 40 weeks. AR activity was also increased causing the elevation of sorbitol in lenses of OLETF rats during the early stages of cataract formation. Despite differences in the etiology of diabetes mellitus, the strain of rat and the rate of disease progression in the OLETF rat model compared with other diabetic models, the present results support the theory that the polyol pathway via AR is a factor in the development of sugar cataracts.

Aldehyde Reductase↗